JPS6027361Y2 - fiber optic connector - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a detachable optical fiber connector used for optical signal processing such as optical communication.

Generally, an optical fiber connector consists of a plug into which an optical fiber is inserted and fixed, and a hollow cylindrical sleeve into which the plugs are fitted and aligned.

In particular, unlike conventional electrical connectors, it is important to accurately align the relative positions of the two fibers to be connected, and for this reason, it is necessary to extremely minimize axial misalignment, angular misalignment, etc. between the optical fibers.

Therefore, there is a method in which the optical fiber is aligned with the center of a cylindrical plug whose outer diameter is finished to a specified size (hereinafter referred to as 6-out), the plug is inserted from both ends of the sleeve, butted together, and the axis of the optical fiber is aligned. Often used.

Currently, there are two types of methods: a method in which this centering is finely adjusted using an adjustment mechanism, and a method in which the centering is performed with increased mechanical precision.

FIG. 1 shows an example of a typical connector of the former type.

That is, the optical fiber wire 3, which is covered in order from the outside with the stainless steel pipe 1 and the glass capillary tube 2, is centered within the metal collar 4 by relative fine adjustment using an optical method using a fine adjustment device, and then the adhesive is applied. It is fixed at 5.

6 is an optical fiber core.

However, this method takes time for centering work and the work process is complicated, so it cannot be said that it is necessarily suitable for mass production.

On the other hand, FIG. 2 shows the latter with improved mechanical precision, in which a minute hole 8 is machined in the center of the plug 7 so that the optical fiber 3 can just barely fit therein.

This connector is characterized in that it is very easy to assemble, as it requires no centering, just by inserting and fixing the optical fiber into the plug 7.

However, the outer diameter of the plug 7, the inner diameter of the microscopic fiber insertion hole 8, and the amount of eccentricity thereof naturally require high-precision machining.

Furthermore, the parallelism of the microhole 8 to the axis is also one of the important requirements for the plug.

The plug with the structure shown in Figure 2 has a microhole and a long hole following it, so it is difficult to make the microhole parallel to the axis, and there is a processing limit to the depth of the microhole. When the fiber is inserted, it is expected that angular deviation will occur due to play between the two.

In the structure shown in FIG. 2, a metal material is usually used.

In order to correct the eccentricity between the microhole and the outer circumferential surface, one idea is to support the microhole and the other end of the plug at their respective conical centers, and polish or cut the outer circumferential surface while rotating the plug. However, since it is a metal material, the large surface is deformed or worn out, making it impossible to apply the above method.

As described above, conventional optical fiber connectors have problems in performance and mass productivity, and are particularly inadequate for realizing high-precision connections.

The present invention eliminates these drawbacks by providing a high-precision optical connector that has a simple structure, does not require centering, is suitable for mass production, and is stable against mechanical shock.

FIG. 3 shows the structure of the plug of the optical fiber connector of the present invention.

This plug consists of two pieces.

Specifically, one is a cylindrical metal collar 9 made of a metal material with excellent weather resistance, corrosion resistance, and strength, such as stainless steel.

The other is a capillary 11 made of a sintered material that is installed and fixed inside the tip 10 of the metal collar 9 and has an outer diameter equal to the inner diameter of the metal collar 9 but slightly medium.

The center of the capillary 11 has a microhole 12 having a diameter slightly larger than the optical fiber 3 by about 1 μm, and a tapered portion 13 is provided on the rear surface to facilitate insertion of the fiber.

The dimensional accuracy of the outer peripheral surface of the tip 10 of the metal collar 9 is 1.
It is less than μ skin, and its shape, such as roundness, 9 cylindrical degrees, and 9 surface roughness, is strictly controlled.

Furthermore, in the assembled plug, the eccentricity between the microhole 12 and the outer periphery of the metal collar 9 is controlled to be 2 μm or less.

Therefore, the jacket of the optical fiber core wire 6 is peeled off, the optical fiber core wire 6 is inserted and fixed as the optical fiber wire 3, and the tip surface is polished, or the end surface of the optical fiber wire 3 is made to have a mirror-like state. By cutting, inserting, and fixing, it is possible to realize a highly accurate optical fiber plug.

One of the features of the present invention is that a ceramic sintered material is used for the capillary, which provides the following advantages.

The advantage of Figure 1 is that it can be fired into any shape with a pilot hole in advance, and its hardness is four times that of glass (or quartz glass), which is about the same as ruby. Since it is so large, even long, cylindrical holes can be made with high precision by polishing.

As a result, mass production is possible, and during grinding to correct the eccentricity between the microhole and the outer circumferential surface, there is a particularly high stress when grinding while supporting the microhole of the capillary and the rear end of the metal collar. It has the advantage of being strong enough to withstand even near the microscopic holes that are subjected to high temperatures, and does not suffer from deformation or wear unlike when using metal materials.

The second advantage is that when inserting a glass-based fiber, ceramic and glass are very compatible and can be easily inserted with a skin clearance of only 1μ, which increases the eccentricity between the fiber and the outer diameter of the plug. There is no risk of it happening.

This is presumed to be because the ceramic sintered material is porous, and when the glass fiber is inserted, the contact surface with the fiber surface becomes substantially smaller.

Another feature of the present invention is that the capillary made of sintered ceramic material is completely covered with a metal sheath.

Therefore, not only can the above-described advantages of the ceramic sintered material be utilized, but also the disadvantage of being vulnerable to mechanical shock, which is a concern when the ceramic portion is exposed, can be covered.

FIG. 4 is a basic configuration diagram showing that the plug of the connector of the present invention is connected via an adapter.

Therefore, when the plugs into which the fibers have been inserted are inserted from both sides of the adapter 16, which is a hollow cylindrical sleeve, and the plugs 19 and 17' are connected, of course, the optical fibers 3 and 3' themselves also have an extremely small axis misalignment. , the connection will be made with an angular deviation, and a high-precision connection will be maintained.

Next, a method for manufacturing the connector plug of the present invention will be explained.

FIG. 5 is a diagram showing an outline of the manufacturing process, which can be broadly divided into a manufacturing process 200 for the capillary 11 made of sintered material, a material processing process 210 for the metal collar 9 such as stainless steel, and a three-dimensional process for assembling these to complete production. There are two processes.

First, the processing of the capillary 11 will be described.

A sintered material, for example, a ceramic raw material containing alumina as a main component, is mixed in a mixing step 201, and then a molding step 202.
Form into a cylindrical shape and make a pilot hole of 20 to 100 μm in the center, or mold the entire pilot hole.

Then, it is fired in a firing step 203. Naturally, firing will cause the outer dimensions to shrink, so the outer diameter should be made larger to allow for shrinkage.

Fired ceramics have extremely high hardness, and it is extremely difficult to drill holes after firing. However, as mentioned above, a pilot hole is pre-drilled, so a wire is passed through this pilot hole and the diamond is inserted. - Hole polishing is performed in the hole polishing step 204 using paste or the like to finish the hole to a predetermined minute diameter.

Next, in the outer diameter finishing step 205, a wire is passed through the center hole and centerless processing is performed based on the hole.

Furthermore, both the hole polishing step 204 and the outer diameter finishing step 205 are performed simultaneously using the same polishing method as the hole stone processing for watch bearings, and it is easy to finish the outer diameter accuracy, hole diameter accuracy, eccentricity, etc. with 1 to 2 μm. Furthermore, it is possible to process hundreds of pieces at a time by passing a wire through the prepared hole in the fired material.

Next, the end face is finished in an end face finishing step 206, and chamfering is performed in a chamfering step 207 to complete the capillary.

On the other hand, the material processing step 210 for the metal collar can be carried out using stainless steel bars using any known method, but it is particularly efficient to carry out using an automatic inn used for precision processing in the watch industry. It is true.

That is, except for the flange portion 14, the outer shape and the hole are continuously machined at one time.

The outer shape processing step 211 is followed by the collar processing step 212 and the collar driving step 213.

Since the material for the metal collar 9 is now completed, an assembly step 220 is performed in which the capillary 11 is assembled and fixed in the hole at the tip.

The processing of the plug is completed with the above steps, but a third step is performed in order to obtain a high-performance plug with reduced eccentricity between the microhole 12 of the capillary 11 and the outer diameter of the metal collar 9.

The reason for performing this third step is to avoid mutual misalignment that occurs when fixing the capillary 11 and the metal collar 9, or the eccentricity of the inner and outer diameters of the metal collar 9 and the capillary 11.
This is because the eccentricity of the outer diameter and inner diameter of the shaft is accumulated.

For this reason, this is an extremely important step, and as shown in FIG. Press the workpiece with the center of the metal collar, etc., and while rotating the workpiece,
Grind the outer periphery.

This is the outer periphery grinding step 221 performed using a so-called outer periphery grinder.

This machining accuracy is extremely high, and both the outer diameter precision and the eccentricity between the microhole and the outer diameter are less than 1 to 2 μm.

By grinding the end face of this in an end face grinding step 222, a plug is completed.

Furthermore, as an actual connector, fiber terminal processing 223
After removing part of the optical fiber jacket,
The fiber is inserted and fixed into the plug in the insertion/fixation step 224, and then the metal collar, the capillary, and the outer end surface of the optical fiber are simultaneously ground again in the end face grinding step 225 to complete the plug assembly. The plugs are then fitted into the hollow cylindrical sleeve and aligned.

Finally, we show the measurement results obtained using the invented connector plug.

Figure 6A shows the capillary microhole diameter (target value is 152μr).
Figure 6B shows the variation in the outer diameter of the metal collar (rL).
The standard value is 2499rIr! n), all of which are about ±1 μm, and furthermore, the eccentricity of the microhole and the outer diameter of the metal collar is 1.3 μm on average, as shown in Figure 6C.
A highly accurate result of eggs was obtained.

As shown in Fig. 6 and Fig. 6E, good shape accuracy of 0.2 μU was obtained for the roundness and surface roughness of the outer peripheral surface of the metal collar.

In addition, fibers were inserted into these loop plugs, the end faces were polished, and the plugs were connected through sleeves in the same manner as explained in Fig. 4, and the connection loss was measured.
It was 0.42 dB.

We have confirmed that this provides the same excellent performance as conventional optical fiber connectors.

As another example using the plug of the present invention, as shown in FIG. There is a method of inserting the glass capillary tube 18 into the plug and fixing it with adhesive 5.

This method allows the fiber wire 3 to be completely integrated with the metal collar 9 using the glass capillary tube 18 and adhesive 5, and has the advantage that it will not break even if the fiber core wire is pulled from the outside, and stable operation can be expected. There is.

As explained above, according to the present invention, it is possible to process a plug having a structure in which a capillary made of sintered material is surrounded by a stainless metal collar on the outside with extremely high precision and by a method that can be mass-produced. Furthermore, by simply inserting and fixing the fiber into the capillary, the center of the plug and the fiber axis can be aligned accurately, and then the plugs with their fiber end surfaces polished are inserted into the cylindrical sleeve. By aligning and fixing the fibers, a high-performance optical fiber connector can be realized.

Furthermore, the connector can be assembled directly on-site at any location, whether indoors or outdoors, without using any special assembly equipment, which is extremely effective.

[Brief explanation of the drawing]

1 and 2 show a conventional optical fiber connector plug, A is a longitudinal sectional view, B is a transverse sectional view, and FIG. 3 is an embodiment of the connector plug of the present invention, A is a longitudinal sectional view. Figure, B
is a cross-sectional view, FIG. 4 is a vertical cross-sectional view showing the basic connection configuration of the plug and adapter of the connector of the present invention, FIG. 5 is a block diagram showing the manufacturing process of the plug of the connector of the present invention, and FIG. Actual measurement data on the shape and dimensions of the plug of the invented connector, A is a diagram showing the actual measurement of the microhole diameter of the capillary, B is a diagram showing the actual measurement of the outer diameter of the metal collar, and C is the outer diameter of the microhole and metal collar. , D is a diagram showing the measured value of the outer peripheral surface roundness of the metal collar, E is a diagram showing the measured value of the outer peripheral surface roughness of the metal collar, and Figure 7 is the plug of the connector of the present invention. It is a longitudinal cross-sectional view which shows another Example. 1... Stainless steel pipe, 2... Glass capillary tube, 3, 3'... Optical fiber wire, 4...
...Metal color, 5...Adhesive, 6,6
′...Optical fiber core wire, 7...Plug, end...Minute hole, 9...Metal collar, 1
0...Metal collar tip, 11.11'...
... Capillary, 12 ... Capillary microhole, 13 ... Capillary taper part, 14 ...
...Metal collar one flange part, 15...Metal collar taper part, 16...Adapter, 17, 17'...
...Plug, 18 ...Glass capillary, 20
0... Capillary manufacturing process, 201...
・Raw material mixing process, 202... Molding process, 203
...Firing process, 204... Hole polishing process, 205... Outer diameter finishing process, 206...
... End face finishing process, 207... Chamfering process,
210... Metal color material processing process, 211.
...Outer shape processing process, 212...Brim part processing process, 213...Brim driving process, 220.
... Plug assembly process, 221 ... Outer periphery grinding process, 222 ... End face polishing process, 223
...Optical fiber terminal processing step, 224...
・・Eye bar insertion fixing process, 225 ・・・End face polishing process.

Claims (1)

[Claims for Utility Model Registration] An optical fiber connector for connecting optical fibers by inserting plugs from both ends of an adapter, the plug comprising a capillary made of a ceramic sintered material and an outer circumference of the capillary. The optical fiber is held in a microhole provided in the center of the capillary, and the end face of the plug is aligned with the end faces of the metal sheath, the capillary, and the optical fiber. The length of the capillary is not smaller than the outer diameter of the capillary, and the optical fibers are butt-connected by fitting and aligning the plugs in an adapter having a built-in hollow cylindrical sleeve. connector.